Crankcase ventilation inside-out flow rotating coalescer

Abstract

An internal combustion engine crankcase ventilation rotating coalescer includes an annular rotating coalescing filter element, an inlet port supplying blowby gas from the crankcase to the hollow interior of the annular rotating coalescing filter element, and an outlet port delivering cleaned separated air from the exterior of the rotating element. The direction of blowby gas is inside-out, radially outwardly from the hollow interior to the exterior.

What is claimed is: 
     
       1. An internal combustion engine crankcase ventilation rotating coalescer separating air from oil in blowby gas from a crankcase, comprising:
 a coalescing filter assembly comprising:
 an annular rotating coalescing filter element comprising a gas permeable fibrous filter media through which said blowby gas is passed so as to cause coalescence of oil on said filter media, the filter media having an inner periphery defining a hollow interior, and an outer periphery defining an exterior, 
 an inlet port supplying said blowby gas from said crankcase to said hollow interior, 
 an outlet port delivering cleaned separated air from said exterior, and 
 an axial end cap on said annular rotating coalescing filter element, said axial end cap engages said inlet port; 
 
 wherein direction of blowby gas flow is inside-out, namely radially outwardly from said hollow interior to said exterior; 
 wherein oil in said blowby gas is forced radially outwardly from said inner periphery by centrifugal force caused by rotation of said coalescing filter element, to reduce clogging of said coalescing filter element otherwise caused by oil sitting on said inner periphery, and to open more area of said coalescing filter element to flow-through, whereby to reduce restriction and pressure-drop; and 
 wherein said centrifugal force caused by rotation of said coalescing filter element pumps said blowby gas from said crankcase to said hollow interior. 
 
     
     
       2. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein said centrifugal force drives said oil radially outwardly from said inner periphery to said outer periphery to clear a greater volume of said coalescing filter element open to flow-through, to increase coalescing capacity. 
     
     
       3. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 2  wherein separated oil drains from said outer periphery. 
     
     
       4. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 3  comprising a drain port communicating with said exterior and draining separated oil from said outer periphery. 
     
     
       5. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein pumping of said blowby gas from said crankcase to said hollow interior increases with increasing speed of rotation of said coalescing filter element. 
     
     
       6. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 5  wherein said increased pumping of said blowby gas from said crankcase to said hollow interior reduces restriction across said coalescing filter element. 
     
     
       7. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein said centrifugal force creates a reduced pressure zone in said hollow interior, and wherein said reduced pressure zone sucks said blowby gas from said crankcase. 
     
     
       8. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein said coalescing filter element is driven to rotate by magnetic coupling to a component of said engine. 
     
     
       9. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein pressure drop across said coalescing filter element decreases with increasing rotational speed of said coalescing filter element. 
     
     
       10. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein oil saturation of said coalescing filter element decreases with increasing rotational speed of said coalescing filter element. 
     
     
       11. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein oil drains from said outer periphery, and wherein the amount of oil drained increases with increasing rotational speed of said coalescing filter element. 
     
     
       12. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 1  wherein oil particle settling velocity in said coalescing filter element acts in the same direction as the direction of air flow through said coalescing filter element. 
     
     
       13. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 12  wherein said air flow passing through said coalescing filter element in said same direction enhances capture and coalescence of said oil particles by said coalescing filter element. 
     
     
       14. A method for reducing crankcase pressure in an internal combustion engine crankcase generating blowby gas, the method comprising:
 providing a crankcase ventilation system including a coalescing filter element separating air from oil in said blowby gas; 
 providing said coalescing filter element as an annular gas permeable fibrous filter media element having a hollow interior, the coalescing filter element including an axial end cap that engages an inlet port; 
 supplying said blowby gas to said hollow interior while rotating said coalescing filter element to pump said blowby gas out of said crankcase and into said hollow interior due to centrifugal force caused by rotation of said coalescing filter element forcing said blowby gas to flow radially outwardly through said filter media element, said pumping effecting reduced pressure in said crankcase. 
 
     
     
       15. An internal combustion engine crankcase ventilation rotating coalescer separating air from oil in blowby gas from said crankcase, comprising a coalescing filter assembly comprising an annular rotating coalescing filter element comprising a gas permeable fibrous filter media through which said blowby gas is passed so as to cause coalescence of oil on said filter media, the filter media having an inner periphery defining a hollow interior, and an outer periphery defining an exterior, an inlet port supplying said blowby gas from said crankcase to said hollow interior, and an outlet port delivering cleaned separated air from said exterior, further comprising an axial end cap on said annular rotating coalescing filter element, wherein said axial end cap is substantially sealed to said inlet port such that in at least one operating condition, little or no blowby gas bypasses said annular rotating coalescing filter element. 
     
     
       16. The internal combustion engine crankcase ventilation rotating coalescer according to  claim 15 , wherein said inlet port is sealed to said coalescing filter assembly and said axial end cap abuts said coalescing filter assembly.